ABOUT THE OPTIONS:
5.56mm NATO or .300BLK?
A common question! It really comes down to what you want to do with it. If you are looking for a harder hitting round up close, that suppresses extraordinarily well, then you're looking for the .300BLK. If you would like a little extra reach with a flatter shooting cartridge, the 5.56mm is what you're looking for. Any more questions on the subject? Read our blog post on the best AR 15 calibers.
A2 Style Flash Hider or Compact Muzzle Brake? While mostly a matter of looks or preference, some states have outlawed A2 Style Flash Hiders or consider them to be "evil features", contributing toward what may or may not be considered an "assault rifle" under the definition of state law. Be sure to read and understand your local laws. Aside from the legality, there are benefits in looks and performance when choosing a Compact Muzzle Brake. Muzzle brakes, besides looking cool, divert the gases exiting the barrel in such a way that reduces recoil and muzzle rise, and can improve follow-up shot speed. Check out our blog on muzzle brakes for more information.
Don't forget to pick up a pistol brace for your build.